Reduction in Specific Contact Resistivity to n⁺ Ge Using TiO₂ Interfacial Layer

We report a metal–insulator–semiconductor (MIS) contact using aTiO₂interfacial layer on highly dopedn⁺Ge to overcome the problem of metal-Fermi-level pinning on Ge, which results in a large electron barrier height. A specific contact resistivity of1.3 × 10⁻⁶\ Ω²was achieved, which represents a 70×reduction from conventional contacts. For the first time, interfacial layer conductivity is experimentally identified as an important consideration for high-performance MIS contacts. New insights on the mechanism responsible for contact resistance reduction are presented.